Now the space travel/automotive/solar power entrepreneur is making some significant progress towards that goal.
The tunnels for the Boring Company will begin "across from my desk at SpaceX", which is located near "Crenshaw and the 105 Freeway", about five minutes from LAX, Musk said earlier this year.
The permit will allow Musk's tunnelling firm to perform, as The Washington Post reports, "some preparatory and excavation work" in a fenced-off auto park in the city's NoMa district. The state of Maryland gave Musk the permission to start digging a 10.3-mile tunnel beneath the Baltimore-Washington Parkway in October, marking the first part of the NY to D.C. route. It was issued November 29.
"We're just beginning, in the mayor's office, our conversation to get an understanding of what the general vision is for Hyperloop", said a spokesperson for the department. Asked whether the Bowser administration supports the project, he was somewhat upbeat but noncommittal, adding: "We're open to the concept of moving people around the region more efficiently".
However, the kind of infrastructure required for the US-wide Hyperloop system Musk dreams of could take decades to build, and we're barely out of the starting gate with this permit.
Hyperloop One is the most prominent of these companies, having already reached speeds of over 200mph on its Nevada test track, while announcing plans for a network of services throughout Europe.
Meanwhile, his proposal for a "hyperloop" - a sci-fi-influenced tube that would launch passengers to their destinations at 600 miles per hour - has inspired the launch of a handful of companies that are trying to make the technology a reality, including Richard Branson's Virgin Hyperloop One. But with Musk's track record such as the Hyperloop project in other areas, experts think it is likely his solution will succeed.